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Cratons of South America and Africa during the Triassic Period when the two continents were joined as part of the Pangea supercontinent. A craton (/ ˈ k r eɪ t ɒ n / KRAYT-on, / ˈ k r æ t ɒ n / KRAT-on, or / ˈ k r eɪ t ən / KRAY-tən; [1] [2] [3] from Ancient Greek: κράτος kratos "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two ...
A craton is an ancient part of the Earth's continental crust which has been more or less stable since Precambrian times. Cratons whose ancient rocks are widely exposed at the surface, often with relatively subdued relief, are known as shields.
The West African Craton (WAC) is one of the five cratons of the Precambrian basement rock of Africa that make up the African Plate, the others being the Kalahari craton, Congo craton, Saharan Metacraton and Tanzania Craton. [1]
The São Luís and the Luis Alves cratonic fragments (Brazil) are shown, but the Arequipa–Antofalla Craton and some minor African cratons are not. Other versions describe the Guiana Shield separated from the Amazonian Shield by a depression, and the Saharan Metacraton as a part of this West African Craton .
The degree of certainty to which the identified landmasses can be regarded as independent entities reduces as geologists look further back in time. The list includes cratons, supercratons, microcontinents, continents and supercontinents. For the Archean to Paleoproterozoic cores of most of the continents see also list of shields and cratons.
Approximate location of Mesoproterozoic (older than 1.3 Ga) cratons within South America–Africa in their Gondwana configuration (c. 550-130 Ma).. The Congo Craton, covered by the Palaeozoic-to-recent Congo Basin, is an ancient Precambrian craton that with four others (the Kaapvaal, Zimbabwe, Tanzania, and West African cratons) makes up the modern continent of Africa.
[22] [23] [24] They used Ar-Ar and U-Pb dating methods and structural evidences including cleavages, lineation and dip and strike data to analyse the Precambrian history of the craton [22] [23] [24] The timing of final amalgamation in their model is in-line with the timing proposed by Zhao, also around 1.8 to 1.9 billion years ago, but another ...
Smaller cratons of Precambrian rocks south of the Amazonian Shield are the Río de la Plata Craton and the São Francisco Craton, which lies to the east. The Río Apa Craton at the Paraguay-Brazil border is considered to be likely just the southern part of the Amazonian Craton. [2] The rocks of Río Apa were deformed during the Sunsás orogeny. [3]